In recent years, the Global System for Mobile Communications (GSM) has grown rapidly all over the world. Along with the development of the GSM and the integration of mobile stations (MS) such as mobile phones and data communications, a plurality of additional services have been implemented.
Among theses services are data services such as the Short Message Service (SMS), which is a bi-directional service in the GSM for short alphanumeric messages, or a service providing access to the Internet using a mobile station.
In case of the SMS, it is possible to deliver a message to the mobile station even during an established call, or to deliver a message using a so-called store-and-forward service, in which the message is stored in the network, if the mobile station is unavailable, and forwarded shortly after the mobile station can be reached again. As for the Internet access, the user can connect to the Internet via the mobile station's IP address and transmit or receive segmented data via the cellular network resources.
In the traditional GSM, data services are based on circuit switched technology providing a maximum user rate of 9.6 Kbit/s for transparent and non-transparent bearer services for data communication. Along with an increasing data volume, demand for higher user rates has arisen, so that the GSM has been developed to include, as an extension, for example the General Packet Radio Service (GPRS) as a packet switched data service.
Packet switching in particular provides advantages over the traditional circuit switching technology in that it only exploits network resources and valuable bandwidth when data is actually being transmitted. Even short gaps between data transmissions leave the network available for other users. On this basis, the GPRS can provide for extremely efficient radio resource utilization with user rates of above 100 Kbit/s.
Even higher user data rates of up to 2 Mbit/s are expected to become available with the future Universal Mobile Telecommunications System (UMTS).
Messages deliverable within the aforementioned data services networks also include a range of mail type messages such electronic mail messages and voice mail messages.
FIG. 2 schematically shows the principle of delivering a voice mail message in the prior art using the traditional GSM.
In FIG. 2, reference numeral 1 denotes a conventional cellular network such as the GSM. Reference numeral 2 denotes a voice mail server within the GSM 1. The voice mail server 2 is provided with a storage means 3 for storing an incoming voice mail message. A dashed line indicates a GSM air connection for exchanging information with a mobile station 4 at the user side.
As shown in FIG. 2, an incoming voice mail message is in the traditional GSM first of all stored in the storage means 3 of the voice mail server 2. The voice mail server 2 then sends an SMS notification to the mobile station 4 so as to alert the user of the stored voice mail message. In order to listen to the message, the user is then required to call the voice mail server 2 from his mobile station 4, which in response then dispatches the stored message.
In the GPRS, the user can activate either the voice service or the packet data service, or can activate both of them simultaneously. However, a mobile station having a simple construction may due to restrictions for reasons of e.g. simplicity in the mobile station implementation and signaling not be capable of following both services simultaneously, so that in this case the user must terminate or suspend the packet data service in order to become able to call the voice mail server and to listen to an arrived voice mail message.
In any case, the user is thus required to observe whether or not a voice mail message is to be retrieved, and then call back the voice mail server to have the message delivered. Inherent to this are drawbacks such as the cost for establishing the connection to the voice mail server each time a voice mail message is indicated at the mobile station, and the operations the user must perform anew each time in order to access the message.
In addition, the voice mail transmission as such has shown to be largely delay insensitive. Up to now, low delay transmission methods are however used in vain when the user is required to listen to a voice mail message stored at the voice mail server in real time.
It is therefore an object of the present invention to provide a voice mail server for delivering a voice mail message, a mobile station for receiving a voice mail message, and a corresponding method therefor, which allow to automatically dispatch a voice mail message via a connection not necessarily meeting the quality required to transfer speech in real time and, thus, eliminate the need to poll a voice mail server by calling.
This object is achieved by a voice mail server for a cellular network, comprising a receiving means for receiving an incoming voice mail message, an adapting means for adapting the voice mail message into a format suitable for transmission by a network channel which does not meet a delay requirement for delay sensitive information, and a transmission means for dispatching the adapted voice mail message to a mobile station.
The connection used therefor could be a packet channel not guaranteeing the delay of transmission, a low speed channel too slow to transfer speech in real time or any other channel. In particular, in the case of a packet channel, segmentation of the voice mail message would be required as said adaptation.
Furthermore, the said object is achieved by a mobile station for a cellular network, comprising a receiving means for receiving an adapted voice mail message, a readapting means for readapting the received message into a reproducible format, and a reproduction means for reproducing the voice mail message.
In addition, the said object is achieved by a method for dispatching a voice mail message in a cellular network, comprising the steps of: receiving an incoming voice mail message at a voice mail server of said cellular network, adapting the received voice mail message into a format suitable for transmission by a network connection which does not meet a delay requirement for delay sensitive information, dispatching the adapted voice mail to a mobile station, receiving the dispatched voice mail message at the mobile station, and readapting the received voice mail message into a reproducible format.
With the above configurations, it is possible to deliver a voice mail message via a network connection which does not meet the delay requirement for delay sensitive information within a cellular network directly to a mobile station, so that the user can receive the voice mail message automatically and, thus, is no longer required to poll the voice mail server for messages by calling.
In particular, the adapting means preferably includes a packetising means for packetising the compressed voice mail message into data packets suitable for packet-switched transmission.
Advantageously, the voice mail message is adapted and transmitted conforming to GPRS and/or UMTS standards, so that it is possible to transmit a voice mail message even with low quality of service and at the same time use network resources effectively.
By preferably dispatching the voice mail message to an IP address and/or an ISDN address of said mobile station, the reception thereof is possible either if the user has activated the corresponding address or if he is GPRS attached and the network uses network requested context activation.
If the mobile station is unable to receive the message, the voice mail message is preferably redispatched in a predefined manner, for example repeatedly on a regular or configurable basis for a predetermined period of time, or may be queued into a store-and-forward service, whereafter the mobile station is informed of the stored message when it can be reached again.
Preferably, the stored message is then dispatched when the mobile station becomes reachable, or when the mobile station asks for messages or for a certain message.
In a further preferred embodiment of the present invention, the voice mail message is stored in a storage means of the mobile station adapted to store a plurality of voice mail messages.
Advantageously, if it is found that the storage means of the mobile station can not store all voice mail messages waiting at the voice mail server at one time or if it is found that a voice mail message exceeds a predefined size and, thus, can not be stored completely in said storage means at one time, another message is sent to the mobile station indicating that further voice mail messages or a remainder of said large voice mail message are still waiting to be dispatched.
In case of plural messages waiting at the voice mail server, a list of a plurality of stored messages can be dispatched to the mobile station.
In case that a voice mail message is not dispatchable within a predetermined period of time, another message indicating the same can be transmitted to the mobile station. In this case, the user could thereafter query the voice mail server, or have the voice mail server queried automatically by the mobile station.
Further preferably, the mobile station also includes an adapting means for adapting a voice mail message into a format suitable for transmission by a network channel which does not meet a delay requirement for delay sensitive information, and a transmission means for dispatching the adapted voice mail message.
In a further preferred embodiment, the reproduction means at the mobile station also includes a display means for displaying an image or video portion attached to the voice mail message.
Additional embodiments of the present invention are subject of further dependent claims.